The Grenville terrane in the northern Appalachians now exposes the deeply buried parts of the crust that was involved in orogeny from 0.9 to 1.2 billion years ago. Previous work suggests that parts of the Grenville Terrane exposed in Ontario were buried as deeply as 40 to 45 km during metamorphism to upper amphibolite or granulite facies. This research will extend investigations aimed at taking advantage of the opportunity to study processes of movements along ductile faults and uplift and cooling patterns of such deep-seated rocks. A number of isotopic, petrologic and structural techniques will be used to define the metamorphic and geochronological history of the Grenville terrane. Results will help constrain tectonic and geochemical processes, including fluid flow, in deep crustal environments of collisional orogenic zones.